Abstract
The Cys-rich peptide, Phytochelatin (PC) has been shown to play an important role in heavy metal detoxification. However, Arabidopsis transgenic plants overexpressing the PC synthase gene failed to show an increase in Cd tolerance. This suggests that novel factors in addition to PC remain to be identified to improve the heavy metal detoxification in plants.
We have successfully isolated a novel Arabidopsis Cd-sensitive mutant (cds1) by carbon ion beam mutagenesis, which causes large base pair deletions to occur at random loci in the genome. cds1 mutant plants show the same phenotype as PC synthesis mutant plants; they are more sensitive to Cd and Hg than wild type, and also show a slight increase in Zn sensitivity. Genetic analyses and GSH synthesis inhibitor studies revealed that the cds1 phenotype was caused by a recessive single mutation, which was different from those of PC-GSH synthesis mutants.
